Prepare the Cake Pans: Preheat the oven to 180°C (356°F). Lightly grease two 6-inch cake pans with oil, then line their bottoms with parchment paper.
Whisk the Oil and Sugar: Add the vegetable oil and castor sugar to a mixing bowl. Using an electric mixer, whisk at high speed for 2 minutes until the mixture is well combined.
Add the Vanilla and Yogurt: Add the vanilla extract and yogurt to the oil-sugar mixture. Continue whisking for another 2 minutes until the ingredients are thoroughly incorporated.
Mix in the Milk and Lemon Juice: Pour the milk into the bowl and add the lemon juice. Give the wet ingredients one final mix until evenly combined.
Sift the Dry Ingredients: Place a fine-mesh sieve over the mixing bowl. Sift the all-purpose flour, milk powder, and baking soda directly into the wet mixture.
Combine the Cake Batter: Using a silicone spatula, gently fold the dry ingredients into the wet mixture. Continue mixing until the ingredients come together into a smooth, evenly combined batter. Avoid unnecessary mixing.
Fill the Cake Pans: Divide the prepared batter evenly between the two lined 6-inch cake pans. Smooth the batter gently so it is distributed evenly in each pan.
Bake the Cake Layers: Transfer the pans to the preheated oven and bake at 180°C (356°F) for 25–30 minutes, or until the cakes are golden brown. Once baked, remove them from the oven and allow them to cool completely before assembling. Cook the Pineapple Compote: While the cakes bake, combine the chopped pineapple, sugar, and water in a saucepan.Place the pan over low-medium heat and cook, stirring occasionally, until the pineapple softens and the mixture reduces to a thick, jam-like consistency. Cool and Demould the Cakes: Once the cake layers have cooled completely, carefully remove them from their pans. Set the layers aside, ready for assembly.
Prepare the First Cake Layer: Place one cake layer on a serving plate or cake stand. Using a pastry brush, lightly coat the surface with pineapple syrup or sugar syrup.
Pipe the Cream Border: Transfer the whipped cream into a piping bag. Pipe a border around the outer edge of the cake layer, forming a shallow well in the centre to hold the pineapple compote.
Add the Pineapple Filling: Spread the cooled pineapple compote evenly inside the cream border in a single layer.
Add the Second Cake Layer: Spread a little more whipped cream over the pineapple filling, then carefully place the second cake layer on top.
Finish the Cake: Add dollops of whipped cream over the top surface of the cake. Spread the cream evenly to cover the top.
Garnish and Serve: Decorate the finished cake as desired. Slice and enjoy once the cake is assembled.